Re: [PATCH v2 4/5] usb: dwc3: Add function suspend and function wakeup support

[Elson Serrao <quic_eserrao@xxxxxxxxxxx>]

On 1/18/2023 6:18 PM, Thinh Nguyen wrote:
> On Tue, Jan 17, 2023, Elson Roy Serrao wrote:
> > USB host sends function suspend and function resume notifications to
> > the interface through SET_FEATURE/CLEAR_FEATURE setup packets.
> > Add support to handle these packets by delegating the requests to
> > composite layer. Also add support to handle function wake notification
> > requests to exit from function suspend state.
> >
> > Signed-off-by: Elson Roy Serrao <quic_eserrao@xxxxxxxxxxx>
> > ---
> >   drivers/usb/dwc3/core.h   |  1 +
> >   drivers/usb/dwc3/debug.h  |  2 ++
> >   drivers/usb/dwc3/ep0.c    | 12 ++++--------
> >   drivers/usb/dwc3/gadget.c | 36 +++++++++++++++++++++++++++++++++++-
> >   4 files changed, 42 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
> > index 53ded08..5cda645 100644
> > --- a/drivers/usb/dwc3/core.h
> > +++ b/drivers/usb/dwc3/core.h
> > @@ -526,6 +526,7 @@
> >   #define DWC3_DGCMD_SET_ENDPOINT_NRDY	0x0c
> >   #define DWC3_DGCMD_SET_ENDPOINT_PRIME	0x0d
> >   #define DWC3_DGCMD_RUN_SOC_BUS_LOOPBACK	0x10
> > +#define DWC3_DGCMD_DEV_NOTIFICATION	0x07
> >   
> >   #define DWC3_DGCMD_STATUS(n)		(((n) >> 12) & 0x0F)
> >   #define DWC3_DGCMD_CMDACT		BIT(10)
> > diff --git a/drivers/usb/dwc3/debug.h b/drivers/usb/dwc3/debug.h
> > index 48b44b8..0897d9d 100644
> > --- a/drivers/usb/dwc3/debug.h
> > +++ b/drivers/usb/dwc3/debug.h
> > @@ -72,6 +72,8 @@ dwc3_gadget_generic_cmd_string(u8 cmd)
> >   		return "Set Endpoint Prime";
> >   	case DWC3_DGCMD_RUN_SOC_BUS_LOOPBACK:
> >   		return "Run SoC Bus Loopback Test";
> > +	case DWC3_DGCMD_DEV_NOTIFICATION:
> > +		return "Device Notification";
> >   	default:
> >   		return "UNKNOWN";
> >   	}
> > diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
> > index 0c1203d..e05c2b9 100644
> > --- a/drivers/usb/dwc3/ep0.c
> > +++ b/drivers/usb/dwc3/ep0.c
> > @@ -30,6 +30,8 @@
> >   static void __dwc3_ep0_do_control_status(struct dwc3 *dwc, struct dwc3_ep *dep);
> >   static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
> >   		struct dwc3_ep *dep, struct dwc3_request *req);
> > +static int dwc3_ep0_delegate_req(struct dwc3 *dwc,
> > +				 struct usb_ctrlrequest *ctrl);
> >   
> >   static void dwc3_ep0_prepare_one_trb(struct dwc3_ep *dep,
> >   		dma_addr_t buf_dma, u32 len, u32 type, bool chain)
> > @@ -367,7 +369,7 @@ static int dwc3_ep0_handle_status(struct dwc3 *dwc,
> >   		 * Function Remote Wake Capable	D0
> >   		 * Function Remote Wakeup	D1
> >   		 */
> > -		break;
> > +		return dwc3_ep0_delegate_req(dwc, ctrl);
> >   
> >   	case USB_RECIP_ENDPOINT:
> >   		dep = dwc3_wIndex_to_dep(dwc, ctrl->wIndex);
> > @@ -514,13 +516,7 @@ static int dwc3_ep0_handle_intf(struct dwc3 *dwc,
> >   
> >   	switch (wValue) {
> >   	case USB_INTRF_FUNC_SUSPEND:
> > -		/*
> > -		 * REVISIT: Ideally we would enable some low power mode here,
> > -		 * however it's unclear what we should be doing here.
> > -		 *
> > -		 * For now, we're not doing anything, just making sure we return
> > -		 * 0 so USB Command Verifier tests pass without any errors.
> > -		 */
> > +		ret = dwc3_ep0_delegate_req(dwc, ctrl);
> >   		break;
> >   	default:
> >   		ret = -EINVAL;
> > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> > index db4b438..1c958c4 100644
> > --- a/drivers/usb/dwc3/gadget.c
> > +++ b/drivers/usb/dwc3/gadget.c
> > @@ -2346,7 +2346,7 @@ static int __dwc3_gadget_wakeup(struct dwc3 *dwc, bool async)
> >   		return 0;
> >   
> >   	/* poll until Link State changes to ON */
> > -	retries = 20000;
> > +	retries = 30000;
>
> This seems like a fix that needs to be splitted to a separate change.
> read_poll_timeout_atomic() would be useful here (as a separate/unrelated
> change for status polling).
Done.

> >   
> >   	while (retries--) {
> >   		reg = dwc3_readl(dwc->regs, DWC3_DSTS);
> > @@ -2383,6 +2383,39 @@ static int dwc3_gadget_wakeup(struct usb_gadget *g)
> >   	return ret;
> >   }
> >   
> > +static void dwc3_resume_gadget(struct dwc3 *dwc);
> > +
> > +static int dwc3_gadget_func_wakeup(struct usb_gadget *g, int interface_id)
> > +{
> > +	struct  dwc3		*dwc = gadget_to_dwc(g);
> > +	unsigned long		flags;
> > +	int			ret;
> > +
> > +	spin_lock_irqsave(&dwc->lock, flags);
> > +	/*
> > +	 * If the link is in LPM, first bring the link to U0
>
> Reword LMP -> low power.
Sure.

> > +	 * before triggering function remote wakeup.
> > +	 */
> > +	if (dwc->link_state == DWC3_LINK_STATE_U3) {
> > +		ret = __dwc3_gadget_wakeup(dwc, false);
> > +		if (ret) {
> > +			spin_unlock_irqrestore(&dwc->lock, flags);
> > +			return -EINVAL;
> > +		}
> > +		dwc3_resume_gadget(dwc);
> > +		dwc->link_state = DWC3_LINK_STATE_U0;
> > +	}
> > +
> > +	ret = dwc3_send_gadget_generic_command(dwc, DWC3_DGCMD_DEV_NOTIFICATION,
> > +					       0x1 | (interface_id << 4));
>
> Create a macro for 0x1. Something like DWC3_DGCMDPAR_DN_FUNC_WAKE. Also,
> create an macro for interface selection. Maybe
> DWC3_DGCMDPAR_INTF_SEL(interface_id).
Sure.

> > +	if (ret)
> > +		dev_err(dwc->dev, "function remote wakeup failed, ret:%d\n", ret);
> > +
> > +	spin_unlock_irqrestore(&dwc->lock, flags);
> > +
> > +	return ret;
> > +}
> > +
> >   static int dwc3_gadget_set_selfpowered(struct usb_gadget *g,
> >   		int is_selfpowered)
> >   {
> > @@ -3012,6 +3045,7 @@ static void dwc3_gadget_async_callbacks(struct usb_gadget *g, bool enable)
> >   static const struct usb_gadget_ops dwc3_gadget_ops = {
> >   	.get_frame		= dwc3_gadget_get_frame,
> >   	.wakeup			= dwc3_gadget_wakeup,
> > +	.func_wakeup		= dwc3_gadget_func_wakeup,
> >   	.set_selfpowered	= dwc3_gadget_set_selfpowered,
> >   	.pullup			= dwc3_gadget_pullup,
> >   	.udc_start		= dwc3_gadget_start,
> > --
> > 2.7.4
>
> Thanks,
> Thinh